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BACKGROUND AND PURPOSE: Perfusion-based collateral indices such as the perfusion collateral index and the hypoperfusion intensity ratio have shown promise in the assessment of collaterals in patients with acute ischemic stroke. We aimed to compare the diagnostic performance of the perfusion collateral index and the hypoperfusion intensity ratio in collateral assessment compared with angiographic collaterals and outcome measures, including final infarct volume, infarct growth, and functional independence. MATERIALS AND METHODS: Consecutive patients with acute ischemic stroke with anterior circulation proximal arterial occlusion who underwent endovascular thrombectomy and had pre- and posttreatment MRI were included. Using pretreatment MR perfusion, we calculated the perfusion collateral index and the hypoperfusion intensity ratio for each patient. The angiographic collaterals obtained from DSA were dichotomized to sufficient (American Society of Interventional and Therapeutic Neuroradiology [ASITN] scale 3-4) versus insufficient (ASITN scale 0-2). The association of collateral status determined by the perfusion collateral index and the hypoperfusion intensity ratio was assessed against angiographic collaterals and outcome measures. RESULTS: A total of 98 patients met the inclusion criteria. Perfusion collateral index values were significantly higher in patients with sufficient angiographic collaterals (P < .001), while there was no significant (P = .46) difference in hypoperfusion intensity ratio values. Among patients with good (mRS 0-2) versus poor (mRS 3-6) functional outcome, the perfusion collateral index of ≥ 62 was present in 72% versus 31% (P = .003), while the hypoperfusion intensity ratio of ≤0.4 was present in 69% versus 56% (P = .52). The perfusion collateral index and the hypoperfusion intensity ratio were both significantly predictive of final infarct volume, but only the perfusion collateral index was significantly (P = .03) associated with infarct growth. CONCLUSIONS: Results show that the perfusion collateral index outperforms the hypoperfusion intensity ratio in the assessment of collateral status, infarct growth, and determination of functional outcomes.

IntroductionAneurysmal subarachnoid hemorrhage (aSAH) is a rare event associated with significant pregnancy-associated maternal and neonatal morbidity and mortality. The optimal treatment strategy and clinical outcome of aSAH in pregnancy remains unclear. We aimed to investigate the treatment utilizations and outcomes of aSAH in pregnant people.MethodsUsing the 2010-2018 National Inpatient Sample, we identified all birth hospitalizations of women between ages of 18 to 45 associated with subarachnoid hemorrhage and aneurysm treatment were included. Multivariate analyses were used to evaluate the effect of pregnancy state, mode of treatment of aneurysms, severity of subarachnoid hemorrhage on mortality and discharge destination of this cohort. Trends in mode of treatment utilized for aneurysmal treatment in this time interval was evaluated.Results13,351 aSAH with treatment were identified, of which 440 were associated with pregnancy. There was no significant difference in mortality or rate of discharge to home in pregnancy related hospitalization. Worse aSAH severity, chronic hypertension, and smaller hospital size was associated with significantly higher rate of mortality from aSAH during pregnancy. Worse aSAH severity was associated with lower rate of discharge to home. Like the non-pregnant cohort, the treatment of ruptured aneurysms in pregnancy are increasingly through endovascular approaches. The mode of treatment does not change the mortality or discharge destination.ConclusionsPregnancy does not alter mortality or the discharge destination for aSAH. Ruptured aneurysms during pregnancy are increasingly treated endovascularly. Mode of aneurysm treatment does not affect mortality or discharge destination in pregnancy.

BackgroundPrehospital automated large vessel occlusion (LVO) detection in Mobile Stroke Units (MSUs) could accelerate identification and treatment of patients with LVO acute ischemic stroke. Here, we evaluate the performance of a machine learning (ML) model on CT angiograms (CTAs) obtained from 2 MSUs to detect LVO.MethodsPatients evaluated on MSUs in Houston and Los Angeles with out-of-hospital CTAs were identified. Anterior circulation LVO was defined as an occlusion of the intracranial internal carotid artery, middle cerebral artery (M1 or M2), or anterior cerebral artery vessels and determined by an expert human reader. A ML model to detect LVO was trained and tested on independent data sets consisting of in-hospital CTAs and then tested on MSU CTA images. Model performance was determined using area under the receiver-operator curve statistics.ResultsAmong 68 patients with out-of-hospital MSU CTAs, 40% had an LVO. The most common occlusion location was the middle cerebral artery M1 segment (59%), followed by the internal carotid artery (30%), and middle cerebral artery M2 (11%). Median time from last known well to CTA imaging was 88.0 (interquartile range, 59.5-196.0) minutes. After training on 870 in-hospital CTAs, the ML model performed well in identifying LVO in a separate in-hospital data set of 441 images with area under receiver-operator curve of 0.84 (95% CI, 0.80-0.87). ML algorithm analysis time was under 1 minute. The performance of the ML model on the MSU CTA images was comparable with area under receiver-operator curve 0.80 (95% CI, 0.71-0.89). There was no significant difference in performance between the Houston and Los Angeles MSU CTA cohorts.ConclusionsIn this study of patients evaluated on MSUs in 2 cities, a ML algorithm was able to accurately and rapidly detect LVO using prehospital CTA acquisitions.

Collateral status has prognostic and treatment implications in acute ischemic stroke (AIS) patients. Unlike CTA, grading collaterals on MRA is not well studied. We aimed to evaluate the accuracy of assessing collaterals on pretreatment MRA in AIS patients against DSA. AIS patients with anterior circulation proximal arterial occlusion with baseline MRA and subsequent endovascular treatment were included. MRA collaterals were evaluated by two neuroradiologists independently using the Tan and Maas scoring systems. DSA collaterals were evaluated by using the American Society of Interventional and Therapeutic Neuroradiology grading system and were used as the reference for comparative analysis against MRA. A total of 104 patients met the inclusion criteria (59 female, age (mean ± SD): 70.8 ± 18.1). The inter-rater agreement (k) for collateral scoring was 0.49, 95% CI 0.37-0.61 for the Tan score and 0.44, 95% CI 0.26-0.62 for the Maas score. Total number (%) of sufficient vs. insufficient collaterals based on DSA was 49 (47%) and 55 (53%) respectively. Using the Tan score, 45% of patients with sufficient collaterals and 64% with insufficient collaterals were correctly identified in comparison to DSA, resulting in a poor agreement (0.09, 95% CI 0.1-0.28). Using the Maas score, only 4% of patients with sufficient collaterals and 93% with insufficient collaterals were correctly identified against DSA, resulting in poor agreement (0.03, 95% CI 0.06-0.13). Pretreatment MRA in AIS patients has limited concordance with DSA when grading collaterals using the Tan and Maas scoring systems.

IntroductionSuccessful treatment of intracranial aneurysms after flow diversion (FD) is dependent on the flow modulating effect of the device. We aimed to investigate the intra-aneurysmal and parent vessel hemodynamic changes, as well as the incidence of silent emboli following treatment with various FD devices.MethodsWe evaluated the appearance of the eclipse sign in nine distinct phases of cerebral angiography before and immediately after FD placement in correlation with aneurysm occlusion. Angiographic and clinical data of consecutive procedures were analyzed retrospectively. Patients who had successful FD procedure without adjunctive coiling, visible eclipse sign on post embolization angiography, and reliable follow-up angiographic data were included in the analysis. Detailed analysis of hemodynamic data from transcranial doppler after FD was performed in selected patients, such as monitoring for silent emboli.ResultsAmong all patients (N = 65) who met inclusion criteria, complete aneurysm occlusion at 12 months was achieved in 89% (58/65). Eclipse sign prior to FD was observed in 42% (27/65) with unchanged appearance in 4.6% (3/65) of the treated patients. None of these three patients achieved complete aneurysm occlusion. Among all analyzed variables, such as aneurysm size, device type used, age, and appearance of the eclipse sign pre- and post-FD, the most reliable predictor of permanent aneurysm occlusion at 12 months was earlier, prolonged, and sustained eclipse sign visibility in more than three angiographic phases in comparison to the baseline (p < 0.001). Elevation in flow velocities within the ipsilateral vascular territory was noted in 70% (9/13), and bilaterally in 54% (7/13) of the treated patients. None of the patients had silent emboli.ConclusionsIntra-aneurysmal and parent vessel hemodynamic changes after FD can be reliably assessed by the cerebral angiography and transcranial doppler with important implications for the prediction of successful treatment.

BackgroundTargeted eloquence-based tissue reperfusion within the primary motor cortex may have a differential effect on disability as compared with traditional volume-based (thrombolysis in cerebral infarction, TICI) reperfusion after endovascular thrombectomy (EVT) in the setting of acute ischemic stroke (AIS).MethodsWe explored the impact of eloquent reperfusion (ER) within primary motor cortex (PMC) on clinical outcome (modified Rankin Scale, mRS) in AIS patients undergoing EVT. ER-PMC was defined as presence of flow on final digital subtraction angiography (DSA) within four main cortical branches, supplying the PMC (middle cerebral artery (MCA) - precentral, central, postcentral; anterior cerebral artery (ACA) - medial frontal branch arising from callosomarginal or pericallosal arteries) and graded as absent (0), partial (1), and complete (2). Prospectively collected data from two centers were analyzed. Multivariate analysis was conducted to assess the impact of ER-PMC on 90-day disability (mRS) among patients with anterior circulation occlusion who achieved partial reperfusion (TICI 2a and 2b).ResultsAmong the 125 patients who met the study criteria, ER-PMC distribution was: absent (0) in 19/125 (15.2%); partial (1) in 52/125 (41.6%), and complete (2) in 54/125 (43.2%). TICI 2b was achieved in 102/125 (81.6%) and ER-PMC was substantially higher in those patients (P

Cerebrovascular events have emerged as a central feature of the clinical syndrome associated with Sars-CoV-2 infection. This increase in infection-related strokes is marked by atypical presentations including stroke in younger patients and a high rate of hemorrhagic transformation after ischemia. A variety of pathogenic mechanisms may underlie this connection. Efforts to identify synergism in the pathophysiology underlying stroke and Sars-CoV-2 infection can inform the understanding of both conditions in novel ways. In this review, the molecular cascades connected to Sars-CoV-2 infection are placed in the context of the cerebral vasculature and in relationship to pathways known to be associated with stroke. Cytokine-mediated promotion of systemic hypercoagulability is suggested while direct Sars-CoV-2 infection of cerebral endothelial cells may also contribute. Endotheliopathy resulting from direct Sars-CoV-2 infection of the cerebral vasculature can modulate ACE2/AT1R/MasR signaling pathways, trigger direct viral activation of the complement cascade, and activate feed-forward cytokine cascades that impact the blood-brain barrier. All of these pathways are already implicated as independent mechanisms driving stroke and cerebrovascular injury irrespective of Sars-CoV-2. Recognizing the overlap of molecular pathways triggered by Sars-CoV-2 infection with those implicated in the pathogenesis of stroke provides an opportunity to identify future therapeutics targeting both Sars-CoV-2 and stroke thereby reducing the impact of the global pandemic.

Background and purpose: To simulate patient-level costs, analyze the economic potential of telemedicine-based mobile stroke units for acute prehospital stroke care, and identify major determinants of cost-effectiveness, based on two recent prospective trials from the United States and Germany. Methods: A Markov decision model was developed to simulate lifetime costs and outcomes of mobile stroke unit. The model compares diagnostic and therapeutic pathways of ischemic stroke, hemorrhagic stroke, and stroke mimic patients by conventional care or by mobile stroke units. The treatment outcomes were derived from the B_PROUD and the BEST-mobile stroke unit trials and further input parameters were derived from recent literature. Uncertainty was addressed by deterministic and probabilistic sensitivity analyses. A lifetime horizon based on the US healthcare system was adopted to evaluate different cost thresholds for mobile stroke unit and the resulting cost-effectiveness. Willingness-to-pay thresholds were set at 1x and 3x gross domestic product per capita, as recommended by the World Health Organization. Results: In the base case scenario, mobile stroke unit care yielded an incremental gain of 0.591 quality-adjusted life years per dispatch. Mobile stroke unit was highly cost-effective up to a maximum average cost of 43,067 US dollars per patient. Sensitivity analyses revealed that MSU cost-effectiveness is mainly affected by reduction of long-term disability costs. Also, among other parameters, the rate of stroke mimics patients diagnosed by MSU plays an important role. Conclusion: This study demonstrated that mobile stroke unit can possibly be operated on an excellent level of cost-effectiveness in urban areas in North America with number of stroke mimic patients and long-term stroke survivor costs as major determinants of lifetime cost-effectiveness. [ABSTRACT FROM AUTHOR]

Imaging protocols of acute ischemic stroke continue to hold significant uncertainties regarding patient selection for reperfusion therapy with thrombolysis and mechanical thrombectomy. Given that patient inclusion criteria can easily introduce biases that may be unaccounted for, the reproducibility and reliability of the patient screening method is of utmost importance in clinical trial design. The optimal imaging screening protocol for selection in targeted populations remains uncertain. Acute neuroimaging provides a snapshot in time of the brain parenchyma and vasculature. By identifying the at-risk but still viable penumbral tissue, imaging can help estimate the potential benefit of a reperfusion therapy in these patients. This paper provides a perspective about the assessment of the penumbral tissue in the context of acute stroke and reviews several neuroimaging models that have recently been developed to assess the penumbra in a more reliable fashion. The complexity and variability of imaging features and techniques used in stroke will ultimately require advanced data driven software tools to provide quantitative measures of risk/benefit of recanalization therapy and help aid in making the most favorable clinical decisions.

Cerebral ischemia manifests widely in patient symptoms. Along with the clinical examination, imaging serves as a powerful tool throughout the course of ischemia-from acute onset to evolution. A thorough understanding of imaging modalities, their strengths and their limitations, is essential for capitalizing on the benefit of this complementary source of information for understanding the mechanism of disease, making therapeutic decisions, and monitoring patient response over time.

BACKGROUND: Cerebral vasospasm is a serious sequela of traumatic brain injury (TBI) which leads to further neurologic injury subsequent to the initial trauma. The natural history and associated risk factors are not well understood. The objective of this study is to evaluate the clinical and radiographic characteristics of patients with TBI. METHODS: This is a descriptive case series of all patients with TBI who underwent cerebral angiogram for evaluation and rescue therapy for posttraumatic arterial vasospasm (PTV) between October 2017 and November 2019. The association of clinical and radiographic characteristics with cumulative severity of angiographic vasospasm was evaluated. The clinical characteristics comprised of age, sex, Glascow Coma Scale (GCS) and need for surgery. The radiographic characteristics were presence of subarachnoid hemorrhage (SAH), location of SAH, presence of contusion, presence of subdural hemorrhage (SDH), and presence of pseudoaneurysm. RESULTS: Twenty-two patients with PTV were identified requiring 69 cerebral angiograms (mean: 3.2; range: 1–9 angiograms per patient) during this period. The average age upon presentation was 40 years old, 81% of the patients were male sex, and the average GCS was 6.8. 67% of the patients underwent craniotomy or craniectomy. All patients had SAH, although only 60% had cisternal SAH. Parenchymal contusion was noted on 90% as well as SDH in 90%. The PTV was noted between 3 and 19 days after trauma. There was more vasospasm involving proximal arteries and higher severity of vasospasm in patients with cisternal SAH. Otherwise, there was no strong association between the clinical or radiographic characteristics and cumulative severity noted on the angiograms for each patient. CONCLUSION: Posttraumatic vasospasm can be detected as early as posttrauma day 3–19 in patients with TBI and SAH. The absence of cisternal SAH does not rule out the occurrence of the vasospasm during the course of treatment. [ABSTRACT FROM AUTHOR]

Background Neurointerventional robotic systems have potential to reduce occupational radiation, improve procedural precision, and allow for future remote teleoperation. A limited number of single institution case reports and series have been published outlining the safety and feasibility of robot-assisted diagnostic cerebral angiography. Methods This is a multicenter, retrospective case series of patients undergoing diagnostic cerebral angiography at three separate institutions -- University of California, Davis (UCD); University of California, Los Angeles (UCLA); and University of California, San Francisco (UCSF). The equipment used was the CorPath GRX Robotic System (Corindus, Waltham, MA). Results A total of 113 cases were analyzed who underwent robot-assisted diagnostic cerebral angiography from September 28, 2020 to October 27, 2022. There were no significant complications related to use of the robotic system including stroke, arterial dissection, bleeding, or pseudoaneurysm formation at the access site. Using the robotic system, 88 of 113 (77.9%) cases were completed successfully without unplanned manual conversion. The principal causes for unplanned manual conversion included challenging anatomy, technical difficulty with the bedside robotic cassette, and hubbing out of the robotic system due to limited working length. For robotic operation, average fluoroscopy time was 13.2 min (interquartile range (IQR), 9.3 to 16.8 min) and average cumulative air kerma was 975.8 mGY (IQR, 350.8 to 1073.5 mGy). Conclusions Robotic cerebral angiography with the CorPath GRX Robotic System is safe and easily learned by novice users without much prior manual experience. However, there are technical limitations such as a short working length and an inability to support 0.035" wires which may limit its widespread adoption in clinical practice. [ABSTRACT FROM AUTHOR]

Despite ongoing advances in stroke imaging and treatment, ischemic and hemorrhagic stroke continue to debilitate patients with devastating outcomes at both the personal and societal levels. While the ultimate goal of therapy in ischemic stroke is geared towards restoration of blood flow, even when mitigation of initial tissue hypoxia is successful, exacerbation of tissue injury may occur in the form of cell death, or alternatively, hemorrhagic transformation of reperfused tissue. Animal models have extensively demonstrated the concept of reperfusion injury at the molecular and cellular levels, yet no study has quantified this effect in stroke patients. These preclinical models have also demonstrated the success of a wide array of neuroprotective strategies at lessening the deleterious effects of reperfusion injury. Serial multimodal imaging may provide a framework for developing therapies for reperfusion injury.

Objective: This study was undertaken to examine averted stroke in optimized stroke systems. Methods: This secondary analysis of a multicenter trial from 2014 to 2020 compared patients treated by mobile stroke unit (MSU) versus standard management. The analytical cohort consisted of participants with suspected stroke treated with intravenous thrombolysis. The main outcome was a tissue‐defined averted stroke, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours attributed to thrombolysis and no acute infarction/hemorrhage on imaging. An additional outcome was stroke with early symptom resolution, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours attributed to thrombolysis. Results: Among 1,009 patients with a median last known well to thrombolysis time of 87 minutes, 159 (16%) had tissue‐defined averted stroke and 276 (27%) had stroke with early symptom resolution. Compared with standard management, MSU care was associated with more tissue‐defined averted stroke (18% vs 11%, adjusted odds ratio [aOR] = 1.82, 95% confidence interval [CI] = 1.13–2.98) and stroke with early symptom resolution (31% vs 21%, aOR = 1.74, 95% CI = 1.12–2.61). The relationships between thrombolysis treatment time and averted/early recovered stroke appeared nonlinear. Most models indicated increased odds for stroke with early symptom resolution but not tissue‐defined averted stroke with earlier treatment. Additionally, younger age, female gender, hyperlipidemia, lower National Institutes of Health Stroke Scale, lower blood pressure, and no large vessel occlusion were associated with both tissue‐defined averted stroke and stroke with early symptom resolution. Interpretation: In optimized stroke systems, 1 in 4 patients treated with thrombolysis recovered within 24 hours and 1 in 6 had no demonstrable brain injury on imaging. ANN NEUROL 2024;95:347–361 [ABSTRACT FROM AUTHOR]